Water tube boiler



March 28, 1939. E. RoKoRN WATER TUBE BOIL'ER Filed Feb. 4, 1937zwwwwwwwwwwwwws ,ww n.

eM M VP W I UW ,m W E Patented Mar. 28, 1939 T UNITED STATES PATlszNrVoFFicE Application February 4, 1937, Serial No. 124,128 InCzechoslovakia February 11, 1936 3 Ciaims.

This invention relates to water tube boilers with natural watercirculation, that is the water circulates without the aid of pumpingmeans, for all steam pressures.

In steep tube boilers, of which use is frequently made, the nests oftubes are substantially acted on directly by the radiated heat in thefurnace chamber, while the remaining surfaces are heated substantiallyonly by the contact of the flue gases. In order to bring about the watercirculation, a certain number of the tubes are constructed as descendingtubes, through which the water passes from the upper container into thelower container, and these tubes are generally either accommodated inthe rear flues or arranged outside the fiues.

The vaporisation capacity increases with the steam pressure, because thehigher the pressure is, the lower the corresponding Vaporisation heatis. The degree of the vaporisation capacity of a boiler is alsoinfiuenced by the speed of the circulating water, but suificientattention is 'frequently not devoted to this speed.

In many high-pressure boilers, the natural speed of the water isartificially increased by pumping. A great water speed in the tubesdecreases the deposit of fur on the inner Walls and increases thevaporisation capacity. When the vaporisation capacity is great, there isset up in the tubes a greater steam speed, which causes water andconsequently moisture of the vapour to be carried along. In thedescending pipes, the water flows downwards and thesteam generatedrises, whereby disturbances may be brought about in the circulation'whenthe vaporisation capacity is fairly great.

An object of the present invention is to provide a water tube boilerwith an intensive natural circulation, this boiler being furnished withan upper collector for steam and water carried along therewith which isarranged outside the heating chamber and which is connected by tubeswith a preferably Vertical cylindrical container arranged outside theheating chamber on any side of the boiler. In this container, a waterand steam chamber is provided. More than one container may be employedif desired.

By this arrangement, a definite and intensive circulation, practicallydry steam, and the possibility of a correct removal of mud and reductionof the fur deposit are affor-ded.

The above and further objects of the invention will be hereinafterdescribed with reference to the constructional embodiment of a boileraccording to the invention illustrated in the accompanying drawing, inwhich:

Figure l shows diagrammatically a cross section through the boiler, and

Figures 2 and 3 are a side elevation and a plan 5 view respectively ofthe boiler.

A high speed in the tubes is produced by employing tubes having asuitable cross section. If the diameter and the length of each tube aremade such that the speed of the generated steam 10 in the tube isgreater than the speed at which the small steam bubbles rise in theWater, then the bubbles combine to form large bubbles which fill acertain part of the tube and force the water up before them. For thispurpose the length of 15 the water tubes should be so selected withreference to their diameter that the volume of steam generated persecond in each tube fills at least one seventh of the volume of thetube.

If only so much steam has been generated that 20 it fills a part of thetube, the small bubbles rise separately to the top and the water sinksabout them. If a larger bubble rising only owing to buoyancy be formed,the water fiows downwards past this bubble along the walls of the tube.25 Such is the case in heated descending or refiux tubes.

A further important feature of the invention resides in that the heatinggases are guided into contact with the water tubes from the very lowest30 part of said tubes, which generally is not the case, because the flowof gases does not accurately follow the path determined by thetransverse walls of the flue, so that a part of the heating surfaceoften remains unutilised.

From the lower water'drum (Figure 1) water tubes 2 extend, which passobliquely through the furnace chamber and rise to the upper collector 3arranged outside the brickwork. The mixture of steam and water which hasbeen forced into the collector 3 from the tubes 2 by the heating of saidtubes flows out of the collector 3 through the tubes 4 into a Verticalcontainer (or a plurality of containers) arranged laterally of thebrickwork, in which container the steam accumulates at the top and thewater at the bottom, the water returning through the tubes 6 into thewater drum I of the boiler. Above the lower inclined part of the watertubes 2, a steam superheater I!! is arranged. The dot-and-dash linesshow the approximate course of the heating gases, which practicallycover the entire heating surface of the water tubes 2. Steam and aquantity of water which is several times greater when referred to theweight of the steam, pass into the collector 3. The steam is thereforemoist and is thus carried away together with the water from thecollector 3 into the container 5 through a plurality of horizontal tubes4 which are larger than the tubes 2. The water is separated from thesteam in the tubes 4 and fiows at the bottom of the tubes, while thesteam flows at the top. Upon entrance into the container 5, the speed ofthe steam is reduced owing to the much greater cross section, and thelast traces of Water are separated therefrom. Consequently, dry steampasses into the superheater IO, which is very important in particular athigh temperatures, as otherwise various salts and similar substancesemanating from the water carried along travel along with the steam andare deposited in the steam turbine or other apparatus connected to theboiler.

The water in the container 5 slowly sinks and the solid constituentsContained in the water have sufiicient time to be deposited on thebottom of the container, from whence they can be readily removed at F.

Behind the boiler water economisers 8 and 9 (Figure 2) may be provided.The boiler according to the inventon is suitable principally for plantsOperating with a fiuctuating withdrawal of steam, as it has a very largewater and vapour Chamber, so that upon Sudden withd1'awal of steam avery considerable pressure fiuctuation does not occur.

What I claim and desire to secure by Letters Patent of the United Statesis:

1. A water tube boiler having a definite intensive natural watercirculation for all steam pressures, -Comprising a, furnace Chamber, alower water drum disposed in said Chamber, an upper collector arrangedoutside the furnace chamber, steeply inclined water tubes passingthrough the furnace Chamber and Connecting said water drum to the uppercollector, at least one container provided outside the furnace Chamber,the upper portions of said container constituting a steam Chamber andthe lower portion a water Chamber, a tube Connecting the upper collectorto the steam Chamber of the container, and means Connecting the WaterChamber of the container to the Water drum, the outlets of the Watertubes in the upper collector being outside the furnace Chamber and abovethe inlet of the tube Connecting the collector to the steam Chamber ofthe container to prevent any back fiow of Water through the Water tubes.

2. A Water tube boiler having a definite intensive natural waterCirculation for all steam pressureS, Comprising a furnace Chamber, alower water drum disposed in said Chamber, an upper collector arrangedoutside the furnace Chamber, steeply inclined water tubes passingthrough the furnace' Chamber and connecting said water drum to the uppercollector, at least one container provided outside the furnace chamber,the upper portons of said container Constituting a steam Chamber and thelower portion a Water Chamber, a plurality of tubes Connecting the uppercollector to the steam Chamber of the Container, and means connectingthe water chamber of the container to the water drum, the outlets of thewater'tubes in the upper collector being outside the furnace Chamber andabove the inlets of the tubes Connecting the collector to the steamChamber of the container to prevent any back flow of water through thewater tubes, the diameter and the length of said second-mentioned tubesbeing such that the steam passing through these tubes has sufiicienttime to separate from the Water before it reaches the steam Chamber ofthe container so that the Water will fall down into the Water Chamber ofsaid Container.

3. A water tube boiler having a definite intensive natural waterCirculation for all steam pressures, comprising a furnace Chamber, alower Water drum disposed in said Chamber, an upper collector arrangedoutside the furnace Chamber,

steeply inclined water tubes passing through the furnace Chamber andConnecting said Water drum to the upper collector, at least onecontainer provided outside the furnace Chamber, the upper portions ofsaid container constituting a steam Chamber and the lower portion awater Chamber, a plurality of tubes Connecting the upper collector tothe steam Chamber of the container, and means connecting the waterChamber of the container to the water drum, the outlets of the watertubes in the upper C01- lector being outside the furnace Chamber andabove the inlets of the tubes Connecting the Collector to the steamChamber of the container to prevent any back flow of Water through thewater tubes, the diameter and the length of said second-mentioned tubesbeing such that the steam passing through these tubes has sufcient timeto separate from the water before it reaches the steam Chamber of thecontainer, so that the Water will fall down into the Water Chamber ofthe said container and the water tubes being of such a diameter andlength that the volume of steam generated per second in each Water tubefills at least one seventh of the volume of the tube.

ERMIN POKORN.

